Please read the vignette.
Or, after installation, the help page:
#> Mock the Unix Make Utility
#>
#> Description:
#>
#> Use R as a minimal build system. This might come in handy if you
#> are developing R packages and can not use a proper build system.
#> Stay away if you can (use a proper build system).
#>
#> Details:
#>
#> You will find the details in
#> 'vignette("An_Introduction_to_fakemake", package = "fakemake")'.
You can install fakemake from gitlab with: